Pressure vessels

ABSTRACT

A CLOSURE ASSEMBLY FOR PRESSURE VESSELS, SUCH AS BOILERS, HEAT EXCHANGERS AND AUTOCLAVES WHEREIN AT LEAST TWO MEDIUMS ARE PASSED IN HEAT EXCHANGE RELATIONSHIP THERETO AND WHEREIN EACH MEDIUM IS UNDER A SEPARATE PRESSURE WHEREBY THE DIFFERENTIAL MAY BE OF RELATIVELY HIGH MAGNITUDE. A TUVE SHEET IS POSITIONED WITHIN THE END CLOSURE MEMBER OF THE VESSEL ON A SHOULDER PORTION THEREOF. A RETAINING RING ASSEMBLY IS INSERTED INTO THE CLOSURE MEMBER AND COOPERATES WITH A SHOULDERED PORTION ON THE TUBE SHEET TO RESTRAIN THE LATTER WITHIN THE CLOSURE MEMBER. A COLLECTION RING IS THEREAFTER AFFIXED ABOUT THE RETAINING RING ASSEMBLY TO FORM A COLLECTION ZONE. LATERALLY SPACED APART FROM SAID TUBE SHEET, TO FORM AN INLET ZONE WITH AN INLET CONDUIT PROVIDED IN SAID CLOSURE MEMBER, IS A COVER WHICH IS SIMILARLY POSITIONED WITHIN SAID CLOSURE MEMBER AS THE TUBE SHEET. A SECOND RETAINING RING ASSEMBLY AND COLLECTION RING ARE FITTED AND AFFIXED, RESPECTIVELY TO FORM A SECOND COLLECTION ZONE.

5:111:20, 1911 SMITH IRESSURE VESSELS Filed Feb. 24, 1970 INVENTOR.

Colin Smith ATTORNEYS United States Patent Oflice 3,605,880 Patented Sept. 20, 1971 US. Cl. 165-158 6 Claims ABSTRACT OF THE DISCLOSURE A closure assembly for pressure vessels, such as boilers, heat exchangers and autoclaves wherein at least two mediums are passed in heat exchange relationship thereto and wherein each medium is under a separate pressure whereby the differential may be of relatively high magnitude. A tube sheet is positioned within the end closure member of the vessel on a shoulder portion thereof. A retaining ring assembly is inserted into the closure member and cooperates with a shouldered portion on the tube sheet to restrain the latter within the closure member. A collection ring is thereafter affixed about the retaining ring assembly to form a collection zone. Laterally spaced apart from said tube sheet, to form an inlet zone with an inlet conduit provided in said closure member, is a cover which is similarly positioned within said closure member as the tube sheet. A second retaining ring assembly and collection ring are fitted and affixed, respectively to form a second collection zone.

This invention relates to pressure vessels, and more particularly to a closure assembly for shell and tube type pressure vessels wherein at least two fluids are passed therethrough which are under diverse pressures of relatively high magnitude differentials therebetween. Such pressure vessels are useful as boilers, heat exchangers, and autoclaves in which chemical reactions take place under high pressure conditions.

Closure assemblies for such vessels have heretofore required sealing gaskets, and when such vessels are being used under relatively high pressure differentials between heat transfer fluids, such systems have failed whereby fluid passing through the high pressure zone will be intermingled with the fluid in the lower pressure zone. Additionally, for horizontally disposed vessels, many difiicult problems are encountered in aligning during assembly the closure head elements including gaskets.

The principal object of the present invention is to provide novel closure assembly for pressure vessels which eliminates the use of sealing gaskets.

Another object of the present invention is to provide a novel closure assembly for pressure vessels operating under conditions of relatively high pressure difierentials between the fluids passing therethrough whereby intermingling of fluids is minimized.

Still another object of the present invention is to provide a novel closure assembly for pressure vessels which allows for ease of alignment during closing operations.

These and other objects of the present invention will become more readily apparent from the following description when taken in conjunction with the accompanying drawing which is a partial side elevational cross-sectional view of a pressure vessel illustrating the closure assembly of the present invention in a closed position.

Referring to the drawing, there is provided a pressure vessel of the tube and sheet type heat exchanger, generally indicated as 10, comprised of a cylindrical chamber 11 to which is aflixed a cylindrical-shaped channel member 12, such as by welding. The channel member 12 is provided with inlet and outlet conduits 13 and 14 provided with fitted inserts 15, and receives a sealing assembly as more fully hereinafter described. The interior surface of the channel member 12 is provided with a first and second thrust shoulder 15a and 16, a circumferentially-forr'ned ridge 17, and a first and second circumferentially-formed grooves 18 and 19. The outer diameter of the first thrust shoulder 15a is less than the inner diameter of the second thrust shoulder 16, with the diameter of the ridge 17 being slightly greater than the outer diameter of the first thrust shoulder 15a and slightly less than the inner diameter of the second thrust shoulder 16.

The pressure vessel 10 is closed by first positioning a disc-shaped tube sheet 30 (including tube 31 positioned within and aflixed thereto) within the channel member 12 until the tube sheet 30 is juxtaposed to the first thrust shoulder 15a. The tube sheet 30 has a generally rectangularly shaped cross-section and is formed with a cylindricalshaped shoulder 32 including an extended arm portion 32a adjacent the point at which the groove 18 is provided within the channel member 12. A substantially rectangularshaped split key ring 33 is placed within the groove 18 of the channel member 12, and is held in the groove 18 by a wedge-shaped retaining ring 33a which cooperates with the shoulder 32 of the tube sheet 30. Axially inward movement of the tube sheet 30 is resisted by engagement of the inner surface of the tube sheet 30 with the shoulder 15a of the channel member 12 whereas movement in the opposite direction is resisted by the split key ring 33 positioned within the groove 18 which is held in place by the retaining ring 33 cooperating with the shoulder 32 of the tube sheet 30.

A looped shaped rigid collecting ring 34 of concave arcuate cross-section is positioned within the channel member 12 in juxtaposition with the ridge 17 and is aflixed thereto and to the arm portion 32a of the tube sheet 30, such as by welding, to form a zone A for receiving and retaining any fluid which may leak about the periphery of the tube sheet from inside the vessel 11.

An L-shaped partition 35 is thereupon affixed, such as by welding to the tube sheet 30 and channel member 12 to provide an inlet zone 36 communicating with inlet 13 and an outlet zone 37 communicating with outlet 14.

A disc-shaped channel member cover 38 is placed within the channel member 12 until the cover 38 is juxtaposed to the second thrust shoulder 16. The cover 38 has a generally rectangularly-shaped cross section and is formed with a cylindrical-shaped shoulder 39 including an extended arm portion 39a adjacent the point at which the groove 19 is provided within the channel member 12. An L-shaped split key ring 40 is placed Within the groove 19 of the channel member 12 and is held therein by a wedge-shaped retaining ring 40a which cooperates with the shoulder 39 of the cover 38. Axial inward movement of the channel cover 38 is resisted by engagement of the inner surface of the cover 38 with the shoulder 16 of the channel member 12 whereas movement in the opposite direction is resisted by the key ring 40 positioned within the groove 19 which is held in place by the retaining ring 40a cooperating with the shoulder 39 of the cover 38. A loop-shaped rigid collecting ring 42 of semi-circular crosssection is positioned over the shoulder area of the cover 38 and is aflixed to the arm portion 39a of the cover 30 and to the channel member 12, such as by welding, to form a zone B" for receiving and retaining any fluid 'which may leak aabout the periphery of the cover 38 past the sealing means from within zones 36 and 37.

It will be appreciated that sealing gaskets known in the art are eliminated by collecting rings 34 and 42. The use of retaining rings 33a and 40a is sufiicient to maintain the split key rings 33 and 40 within the grooves 18 and '19, respectively. This construction permits the use of low alloy steel for the vessel 11 and the channel member 12 thereby eliminating the need for all stainless steel construction. Further, it will be appreciated that high pressure difierentials may be withstood between the fluid in the vessel 11 and zones 36 and 37.

What is claimed is:

1. A closure assembly for a pressure vessel of the tube and sheet type configuration having a closure member including an inlet conduit provided on the pressure vessel which comprises:

a tube sheet positioned within the closure member with the inner surface of the tube sheet in juxtaposition to a shoulder portion formed in said closure member;

a retaining assembly circumferentially positioned about the outer surface of said tube sheet and within said closure member to restrain outward movement of said tube sheet;

a rigid collecting ring circumferentially positioned about said retaining assembly and aifixed to said tube sheet and said closure member forming a collection zone therein;

a cover positioned within said closure member and laterally spaced from said tube sheet forming an inlet zone with said conduit.

2. The closure assembly as defined in claim 1 wherein said collecting ring is of arcuate cross-section.

3. The closure assembly as defined in claim 1 wherein the inner surface of said cover is juxtaposed to a second shoulder portion formed in said closure member.

4. The closure assembly as defined in claim 3 wherein a second retaining assembly is circumferentially positioned about the outer surface of said cover and within said closure member to restrain outward movement of said cover.

5. The closure assembly as defined in claim 4 wherein a second rigid collecting ring is circumferentially positioned about said second retaining assembly and is affixed to said cover and said closure member forming a second collection zone therein.

6. The closure assembly as defined in claim 5 wherein said collecting ring is of substantially semi-circular cross section.

References Cited FOREIGN PATENTS 615,451 2/1961 Canada -158 CARROLL B. DORITY, JR., Primary Examiner US. Cl. X.R. 165-176 

